I've been asked more than once if we've ever found anything valuble (our RE was laughing about that the last time we bought a house as she said she never finds old painting or jewels when she buys a house, she just finds junk!). So the answer to that - is sort of . But the most valuable thing we've found, was not a price tag valuble.
I've found plenty of funny things, I have a pair of safety goggles from the 40's or so that would make any steam punk fan drool. David once endured a hail of Penthouse when he renovated the bathroom in the college rental we bought and he took the drop ceiling down. A lot of tchotchke,tourist souvenirs from Florida, ceramic figurines, a very old biscuit box. My favorite find as everyone knows is the giant purple bridesmaid dress that not only has 6 inch ruffles gracing the bottom but also an underskirt with rows of ruffles. It had been carefully dry cleaned and was in a plastic bag, apparently someone fell for the old " I know it's expensive but you CAN wear it again!". I've owned it for 5 years and I can honestly tell you I have yet to find any occasion suitable despite my trying. When we bought this house the former owner's sister was very kind and left a picture of the house in it's heyday on the fireplace mantel where it has remained. If we ever leave the picture will stay behind because the value of it is not the picture itself, but the subject matter - it's value is to the owner of the house. Which leads us to what David found in the wall upstairs.
When he started gutting and pulling down the walls he found a very old, but intact leather coal mining utility belt. A lot of times things end up behind walls when they renovate which I'm sure is how it ended up there. Despite it's obvious age and being leather it was in one piece, being in a wall probably helped preserve it. Due to it's age and collectability I'm sure it was worth something - I say "was" because I no longer have it. There was a small metal plate which I cleaned gently - it had two things on it. The name of the coal mine - and the name of the coal miner which I recognized immediately because we are friendly with the former owner's niece. She was very excited about our find so the belt went from here to there, but it didn't stop. She called this morning to let me know how happy the family was because the coal miner's grandson is still alive and well and he got the belt yesterday in the mail. They're researching how to have it restored and then later on it will be handed down to this man's grandson - it's officially a family heirloom again and I'm sure if you asked them what the value is, it would be priceless. So the answer to if we've ever found something valuable would be yes, but the value would be in our being able to give it back to someone who will cherish something that they didn't even know they had.